Lathe and like machine tool



July 9, 1935. R. J. DIXON LATHE AND LIKE MACHINE TOO];

7 Sheets-Sheet 1 INVENTOR. REGINALD JOHN DI ON MMB i? ATTORNEV5 July 9,1935. R. J. DIXON LATHE: AND LIKE MACHINE TOOL Filed Dec. 15, 19:54 7Sheets-Sheet 2 Nww R O WW5 W Y N mw m .M N T [0. T .J A 0. L w m F aw mw.

July 9, 1935. R. J. DIXON 2,007,564

LATHE AND LIKE MACHINE TOOL Filed Dec. 13, 1934 '7 Sheets- Sheet. 5

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LATHE ANDLIKE MACHINE TOOL Filed Dec. 15, 1954 7 Sheets-Sheet 5 INVENTOR REGINALD JOHN DIXON ATTORNEYS July 9, 1935. R. J. DIXON LATHE ANDLIKE MACHINE TOOL 7 Shets-Sheet 6 Filed Dec. 13, 1934 INVENTOR REGINALDJOHN DIXON ATTOR N EYS July 9, 1935.- R. J. DIXON 2,007,564

' LATHE AND LIKE MACHINE TQOL Filed Dec. 13, 19:54 7 Sheets-Sheet 7 Y rINVENTOR REGINALD JOHN DIXON ATTORN KY5 Patented July 9, 1935 PATENTOFFICE- LATHE LIKEMACHINE TOOL Reginald John Dixon, Coventry, England,as-

signor to A- C. Wickman Limited, Coventry, England, a British companyApplication December 13, 1934, Serial No. 757,279

In Great Britain November 15, 1933 13 Claims. v (01. 29-41) Thisinvention relates to lathes and like machine tools.

According to the invention mechanism for actuating one or more toolslides or work holders comprises in combination a cam providing rec-""or fulcrums of which is or are moved by the motion derived from one ofthe cams, so that the lever has a variable stroke. Instead of a lever ofvariable stroke, however, it would be possible to use a number oflevers, each having a different stroke, while. still obtaining theadvantages of the cam arrangement and the differential means, althoughthe use of interchangeable levers would be less convenient, and. wouldnot give the infinite possibilities of adjustment obtained by the use ofa variable stroke lever. The means whereby resolution of the motionsderived from the two cams is effected may be varied in several ways, butthe accompanying drawings and diagrams illustrate examples of mechanismfor giving practical effect to the invention.

Figure 1 represents in elevation partly in section, one arrangement ofsuch a mechanism.

Figure 2 is a plan of the mechanism shown in Figure 1.

Figure 3 is a sectional elevation taken on the line 3--3 in Figure 2. k

Figure 4 represents the same mechanism in section on the line 4--4 inFigure 2.

Figure 5 represents in side elevation a form of lathe embodying theinvention. Figure 6 is a sectional view on a larger scale of a portionof the machine shown in Figure 5, taken on the line 6-6 in Figure '7.

Figure '7 is a horizontal section taken on the line 1| in Figure 6.

Figure 8 represents inside elevation another lathe,

'Figure 9 is a cross section of the lathe shown in Figure 8, taken onthe line 9-4 in Figure 8.

Figure 10 is a diagram illustrating/a modification hereinafterdescribed.

In the drawings, Figures 1 to 4, the reference numeral 20 indicates thebase of the mechanism, 2| a shaft on which is a chain sprocket 22, re-

the cam shaft 28, these dogs having inclined faces ceiving a drive fromany convenient source, which drive is transmitted from the shaft 2|through gears 23 and-24 to a worm shaft 25, from which a worm 26transmits rotation to a cam shaft 28,

on which are mounted cams 30, 3|. The cam 30 5 provides the cutting feedand return motion for the tool. The cam 3| provides the rapid idlemovement of the tool, forward and reverse. Each of these cams 30 and 3|is in two parts, the outer members being indicated at 30a and am,respectively. The motion derived from the cam 30 is transmitted by alever 32 and link 33 to a rack 34. The pivot by which the link 33 isconnected to. lever 32 may be clamped at any position along the curved Tslot formed on said lever 32, the motion 15 transmitted to the rack 34varying between zero and a maximum according as the pivot and thefulcrum of lever 32 are closer together or further apart, the motionbeing zero when the pivot and fulcrum are coincident.

During that part of the cycle of the cam 30 when no motion istransmitted to the rack 34, motion is being transmitted by cam 3| to arolling pinion 36 on a slidable member 35, the pinion 36' meshing withboth the stationary rack 34 and a '25 slidable rack 31. The resultantmotion of rack 31 is therefore twice that of the pinion 36, and providesthe rapid forward movement to the tool slide.

During that part of the cycle in which the slidable member and itsassociated pinion 36 derive no motion from the cam 3|, the rack 34 iscaused to slide by the movement of lever 32 transmitted through link 33actuated by cam 30, the motion of rack 34 being transmitted throughpinion 36 to rack 31 connected to the tool slide, to which is impartedthe cutting stroke at the desired rate.

During the cutting stroke, it is preferable that the slidable member 35should be held by the cam against an abutment.

Upon completion of the working stroke, the rack 31 is rapidly returnedto its initial position by simultaneous movement of rack 34 and pinion3B. A friction clutch 40 is actuated through a lever 4|, a slidablemember 42 which carries a block 48 having a pin 49 engaging a slot inthe upper end of the said lever 4|, and dogs 43, 44 mounted on the wormwheel carried on which at the completion of the cutting-stroke engagethe slidable member 42 to rock the lever 4| and thus to engage thefriction clutch 40, causing the worm shaft 25 to rotate at a higherspeed, over-running the drive received from the chain pulley 22, thisbeing permitted by reason 0? the presence of a free wheel 45 on theshaft 25. The higher speed is derived from a chain sprocket 46 which isseparately driven from any convenient source. a

By this mechanism any working stroke of the tool slide from zero to themaximum is obtainable, as determined by the dimensions'of the cam andlever 32, together with an idle rapid stroke which is substantiallyconstant irrespective of adjustments of the working stroke.

Referring now to Figures 5, 6 and 7, which show a modified mechanismembodied in a turret lathe, upon the base or swarf tray 20 is mounted aspindle drum housing 5|, with indexible spindle drum and work spindles52. This spindle drum is indexed and fixed in such a manner that thespindles in succession are always in axial alignment with the fourlongitudinal tool slides 53 and 53A, which are supported by the bed 54and overhead beam 55 respectively. The column 56 contains the gear drivefor the spindles and feed mechanism. A pulley 51 drives the workspindles 52 through suitable gearing and a transmission shaft 58. In thehousing 59 is the mechanism for operating the longitudinal tool slides53 and 53A.

A shaft 60, driven by worm 62 and wheel SI (Figure 7) carries cam discs63. Two of these discs are equipped with cams 64, which operate a forklever 65 having two alternative pivot positions I6 and II. A pinionslide 66 carries four pinions 6I,,with which racks 68, 68A and 69 areconstantly in mesh. The racks 69 are connected by rods I0 to swivellevers II operated by lead cams I2. The two end working slides 53 areeach operated from a rack 68 through the medium of pinions I4 and racksI5. endwise positioning being provided by right and left hand adjustingscrews 80. Similarly the two end working slides 53A are operated fromracks 68A through pinions 14A and lacks 15A.

When the lever 65 has been operated by the cam 64, bringing the pinionslide 66 from its upper position, against stops I3, the pinion slide 66is locked whilst the rollers on the lever 65 are in contact with theperiphery of the concentric cams 64. The downward movement of the pinionslide 66 provides the rapid forward travel of the tools slides 53 and53A, this travel being equal to twice the length of the stroke of thepinion slide 66, as the pinions .61 have rolled along the stationaryrack 69, which has been held in position between cam sections I2 and I8.The variable stroke levers II are now operated by the lead cams I2; theracks 6.9are thus pushed upwards by means of the rods I0. The pinions 61are rotated and transmit motion to the racks 68 and 68A, which are moveddownwards. This provides the working or cutting strokes, the lengths ofwhich are adjustable by locking the rods I0 in the desired position in Tor dovetail slots in the variable stroke levers II. The lower ends ofthese rods I0 can be clamped concentrically with the fulcrum points ofthe levers II so that the .working travel can be zero, if acorresponding slide is-used for recessing or a similar operation. Thereturn strokes are now'efl'ected by return cams -'I8 and I9,simultaneously bringing the levers 65 and II into their originalpositions, that is, the rack 69 is drawn downwards and the pinion slide66 is moved upwards, these combined movements being transmitted bypinions 61, racks 68 and 68A and pinions I4 and 14A to the tool slides.By utilizing the alternative pivot positions I6 or II, the stroke of thepinion slide 66 may be varied,

with consequent alteration in the length of rapid travel of the toolslides.

, Referring now to Figures 8 and 9 on the base or swarf tray 20 is ahousing 5| carrying the drum 82, spindles 52 and overhead beam 55, whichsupports the two overhead cross slides 85. An extension 86 of thehousing carries lower cross slides 81. The work spindles 52 are drivenfrom gearing in the column 89 through the centre drive shaft 88. Thelongitudinal slides 90 are operated by a cam shaft (not shown) in thecolumn 89. A cam shaft 9I driven by worm and wheel carries the cams forindexing, bar feed, etc.,

and also the cam disc 92, which is toothed on its periphery, and thusdrives a cam disc 93 on a shaft 94. These discs 92 and 93 carry on oneside earns 95 which operate the slow or working travel, and on the otherside cams 96 and 91, which effect the fast idle movement of the slides85 and 81. The rapid return travel is obtained when the cam section 96moves a lever 98 through the medium of a roller IOI over towards the camshaft 9|. The lower end of the lever 98 pushes against collars I02 andthus moves a rod I03. Rack teeth on the ends of the rod I03 engage withteeth out in shafts I04" which bear at one side in the main housing 5|and on the other in bushes I05. Each shaft I04 has an eccentricextension which fits into a slot in a pillar I06, the latter being heldagainst rotary movement by a key I01, and locked in the lower or workingposition against the pillar housing by a stop collar I08. The pillar I06provides a bearing for a fulcrum pin I I0, which carries operatinglevers I I2. T slots are milled in the levers I I2 and cary rods I I3and I I4, which connect with I the cross slide operating levers H5 andH6. The-eccentric on the shaft I04 is rotated through degrees by the rodI03 operated by the cams 96 and 91 and the lever 98, thus raising thepillar I06 together with the lever II2. As the roller II 8, on theoperating arm of the lever I I2, is guided between the cam III and thehub of the cam disc 92, the rod II 3 is carried upwards, thustransmitting motion to the cross slides through the levers I I5 and II6. The rapid forward movement of the slides is obtained whenthe lever98 is moved in the opposite direction, by the cam 91 on the cam disc 92,thus reversing the eccentric movement, and locking the pillar I06against the housing by the locking ring I08. The slow orcutting'movement is now effected by the swivel lever II 2 being moved bythe lobe of the form cam 95. .The connecting rods H3 and I I4 with thelevers H5 and H6 again transfer the movement to the lower and uppercross slides. The double sided swivel levers II2 are provided with Tslots on their outer faces, in order that the connecting rods may besteplessly connected from the fulcrum point outwards, thus giving slidemovements from zero to the maximum, without changing the cam. The returnstroke is now obtained, firstly by the return cam section III moving theswivel lever II2 towards the centre of the cam discs 92 and 93, andsecondly, by the pillars I06 being raised by the eccentrics on theshafts I04 as already described. It is tobe noted that by using doublesided cam levers II2 as shown in the drawings, one cam is sufficient tooperate'two cross slides, each slide having an independent length ofstroke.

In another alternative arrangement diagrammatically illustrated inFigure 10, two variable stroke levers I20 and I2I are employed, operatedby the feed cam 30 and the idle movement cam 3|, to give the requiredmovement to the Tool slide I22.

, It will be seen that the various examples described can be appliedboth to the movement of cross slides and for actuating longitudinalslides, in each case two separate cams being employed, from one of whichcams is derived the normal cutting feed motion, and from the other therapid idle movement by which tools are rapidly advanced to the work andrapidly withdrawn, and preferably a variable stroke lever is employed inconjunction with the feed cam, for obtaining varying lengths and ratesof feed. A variable stroke lever may also be employed in conjunctionwith the cam providing the rapid idle stroke for obtaining varyinglengths of idle movement .of slides. The combination of two tooth racksand a rolling pinion constitutes a differential gear,

.and a lever having an adjustable fulcrum, in so far as it can beemployed for resolving two independent motions, is also a differentialgear. The detailed means whereby resolution of mo tions derived from twocams is effected offer a choice of a large number of alternatives, butfor application to machines in which considerations of space areimportant, the means described are considered preferable.

What I claim and desire to secure by Letters Patent of the United Statesis:

1. In a lathe or like machine tool, a mechanism for actuating one ormore tool slides or work holders, comprising in-combination a camproviding rectilinear feed motion transmitted to one element of adifferential gear, a separate cam providing rapid rectilinear motion inboth forward and reverse directions,transmitted to the second element ofthe differential gear, the resultantmotion of the third element of thesaid differential gear being transmitted to the tool slide or slides, orwork holder or holders.

2. Apparatus as in claim 1, in which the respective motions derived fromthe two cams are resolved by the motions of a lever or levers, thefulcrum or fulcrums of which is or are moved by the motion derived fromone of the same.

3. Apparatus as in claim 1, in which the rectilinear feed motion derivedfrom one cam is transmitted toa slidably mounted toothed rack, the rapidrectilinear forward and reverse motions derived from the second cambeing transmitted to a pinion meshing with said rack and causing thepinion to roll along the rack, and a further toothed rack engaging theopposite side of the pinion, transmitting the resultant of the motionsof the pinion and the other rack to the tool slide or slides, or workholder or work holders.

4. Apparatus as in claim 1, in which a lever or levers of adjustablestroke transmit the motions derived from either or both of the cams tothe respective-elements of the mechanism for resolving the motionsderived fromthe two cams, for the purposes described.

5. Apparatus as in claim 1 .wherein for eac tool slide one lead cam isemployed to obtain every length of cutting travel within the capacity ofthe machine, by means of a variable stroke lever to which an operatingrod can be connected at any point from the fulcrum outwards, and also anidle fast travel which is substantially constant, regardless of thecutting length being used, is obtained by means of two racks and aslidable pinion, the movement of which latter produces theidle travel.

6. Apparatus as in claim 1, wherein for each tool slide one lead cam isemployed to obtain every length of cutting travel within the capacity ofthe machine, by means of a variable stroke lever to which an operatingrod can be connected at any point from the fulcrum of said leveroutwards, and also an idle fast travel which is substantially constant,regardless of the cutting length being used, is obtained by means of tworacks and a slidable pinion, the movement of which latter produces theidle travel, and. a slidable pinion meshing on one side with a rack heldstationary during the period in which the pinion is sliding, in order toproduce a double length of stroke of the rack on the opposite side.

7. Apparatus as in claim 1, wherein every length of cutting travel for atool slide or workholder within the capacity of the machine, andan idlefast travel which is substantially constant irrespective of the cuttingtravel, are obtainable by means of two slidably mounted racks meshing onopposite sides of a slidably mounted pinion, one of the said racksderiving motion from a feed cam by means of a variable stroke lever towhich a link attached to the rack can be pivotally connected at anypointfrom thefulcrum of said lever outwards, the pinion being caused to movein rolling relationship with the said rack by a separate cam, the motionof the other rack being transmitted to the tool slide or workholder, theresultant travel of the tool slide actuating rack being twice that ofthe pinion when the other rack is held stationary.

8. Apparatus as in claim 1, wherein the cutting travel derived from onecam is translated by means of an adjustable stroke lever to whichanoperating rod can be pivotally connected at any point from the fulcrumof said lever outwards, the fulcrum receiving motion from a separate camto produce an idle fast travel which is substantially constant.

9. Apparatus as in claim 1, wherein the independently adjustable cuttingtravel for a plurality of tool slides or workholders is derived from onecam by means of a double-sided lever towhich an operating rod or rodscan be pivotally connected at any point from the fulcrum out-' wards oneach side of said lever, the fulcrum of which derives motion from aseparate cam to produce an idle fast travel which is substantiallyfulcrum outwards, the lever fulcrum being mounted on a pillar derivingsliding motion from a separate cam by means of an eccentric rotated by apinion meshing with a slidable rack actuated by a lever bearing upon thesaid separate cam to produce an idle fast travel which is substantiallyconstant. I

11. Apparatus as in claim 1, wherein the cutting travel for a pluralityof slides is derived from one cam by means of a double-sided lever towhich operating rods can be pivotally connected at any points from thefulcrum of said lever outwards, the lever fulcrum being mounted on apillar deriving sliding motion from a sep-v arate cam by means of aneccentric rotated by' a pinion meshing with a slidable rack actuated bya lever bearing upon said separate cam to produce an idle fast travelwhich is substantially constant.

12. Apparatus as in claim 1, wherein the independently adjustablecutting travels for a pludependently adjustable cutting travels for aplurality of tool slides or workholders are derived from cams by meansoi. levers to which operating rods can be pivotally connected at anypoints from the Iulcrums of said levers outwards, the fulcrum 01' eachlever being mounted on a slidable pillar actuated by an eccentricrotated by a pinion, all the pinions associated with all 91 theeccentrics and pillars meshing with a rack actuated by a lever derivingmotion from a separate cam providing simultaneous substantially constantidle fast motion to all the tool slides 10 or workholders.

' REGINALD JOHN DIXON.

